Steps to reproduce:

1. Create a project
2.  Go to "Project" -> "Asset" section -> right click ->Create ->UI Toolkit -> UI Document ->leave default proposed name -> click "Save"
3. Double click on it
4. Verify, that "UI Builder" window opens
5. Select "VisualElement" in "Containers" window and drag it to the "Hierarchy" window as child object for "NewUXMLTemplate.uxml"
6. Observe "Inspector" section

Actual result: User gets overlapping. Added screenshot in the "Attachments" section.

Expected result: User shouldn't get this.

(Old list of steps to reproduce as reported by user):

1. Create a project
2.  Go to "Project" -> "Asset" section -> right click ->Create ->UI Toolkit -> UI Document ->leave default proposed name -> click "Save"
3. Double click on it
4. Verify, that "UI Builder" window opens
5. Drag "UI Builder" tab next to "Game" tab
6. Select "VisualElement" in "Containers" window and drag it to the "Hierarchy" window as child object for "NewUXMLTemplate.uxml"
7. Click "+" in StyleSheets section and create new USS file
8. Select "Label" in "Controls" section and drag into "Hierarchy" window as child for "VisualElement"
9. In "Inspector" section lets add ".header" class in "Style Class List"
10. Verify, that it becomes added
11. Let's delete "Label" from "Hierarchy" section
12. Let's select "VisualElement"
13. Observe "Inspector" section

Actual result: User gets overlapping. Added screenshot in the "Attachments" section.

Expected result: User shouldn't get this.

Reproducible with: 2023.1.0a21, 2023.1.0b7, 2023.2.0a5.

Not reproducible with: 2021.3.20f1, 2022.2.9f1, 2020.3.46f1 (functionality not available).